7() Thirl y-ninth Annual Meeting 



is that our yuarlings do well in any of the ponds, thus adding to the 

 difficulty of solving the problem. The disease occurs only during tl:e 

 sunmier months, and while the fish range in size from No. 2 to No. 4 

 fingerlings. 



Going to another point in fish disease: At one of the commercial 

 hatcheries in Pennsylvania and also in the ponds of an organization in 

 the State which has a private preserve, there appeared a boil-like disease 

 in the throat, similar to a tumor; and probably one fish out of every 7 

 or <S had this disease. I visited the commercial hatchery and found the 

 ponds inexpressibly filthy; some of them had not been cleaned for 10 or 

 12 years ; and in these there was two feet of mud and dirt and filth of all 

 kinds. I recommended the cleaning of the ponds and the construction 

 of new sides. Word was received the other day that the disease had 

 entirely disappeared from the place, giving the idea that this particular 

 disease is caused largely by a filthy condition of the ponds. 



Mr. John W. Titcomd : I think possibly this subject of fish diseases 

 is one that we could discuss the entire time that is allotted for these 

 meetings. It seems to me the chief trouble is not in discovering what 

 the disease is, but in finding a remedy; and until we know more about it 

 every fish culturist must keep his place as clean as possiltle, and thus 

 avoid many diseases which otherwise may creep in. 



The disease at Northville, which has been ably written \^^ by 

 Mr. Marsh, is one for which there appears to be no remedy. It may 

 be possible to have an arrangement whereby something can be put into 

 the water, a minute portion of copper sulphate, for instance, to counter- 

 act tlie effect of the bacteria, but it is ratlier questionable whether this 

 would pay. 



The Bureau has given up the idea of propagating brook trout at 

 Northville, or rather of rearing them and carrying a brood stock, 

 although we raise the fish up to a proper size for distribution as fin- 

 gerlings. We have, however, been experimenting there on the subject 

 of breeding with a view to ascertaining whether it is possible to secure 

 a race of fish which are immune. By attempting to rear 10,000 of these 

 trout to adults, we hope to ascertain whether out of the 10,000 there may 

 be 500 or 1,000 which survive the disease — we would expect them all to 

 have it — and then from these survivors breed a race possibly immune. 

 Tliis is merely an experiment, and though perhaps not of ])ractical 

 \alue, it may jjroduce some results. The so-called throat disease is being 

 \ery thoroughly investigated by the Bureau at this time by a specialist 

 well informed on the subject. It is not generally thought by physicians 

 that the disease is transmitted to the human being, at least if the fish. 

 IS cooked. 



An important point to be ascertained is where the fish first get the 

 disease ; whether it comes from the feeding of hog's plucks or the 

 plucks of other anim.als. Possibly it comes from this source. It nnist 

 lie transmitted through the water from one point to another, which em- 

 l)hasizes the desirability of having each ])ond independently supplied 

 when possible to do so, These problems are being taken up by the 



